EP 0,650,109 A1 describes a pressure reducer with a housing fitting having an inlet socket and an outlet socket. The inlet socket and the outlet socket are aligned and define a common axis and serve to install the housing fitting in a water pipe. The housing fitting has a partition with an aperture. Furthermore, the housing fitting has an accommodation socket, the axis of which is normal to the common axis of the inlet and outlet sockets. The accommodation socket is aligned with the aperture in the partition.
A pressure reducer insert is accommodated by the accommodation socket and by the aperture. This pressure reducer insert has a tapering insert housing. The insert housing has an open wide end and a narrow end. The open wide end is closed by a regulating diaphragm. The regulating diaphragm is connected to a valve stem, which is sealingly guided out of the narrow end of the insert housing. A valve seat is connected with the insert housing through webs. This valve seat is sealingly mounted in the aperture of the partition. The valve stem extends through the valve seat and carries a valve head at its downstream end. The valve seat and the valve head represent a regulating valve. The outlet pressure downstream of the regulating valve is transmitted to a controlled pressure chamber defined by the insert housing and the regulating diaphragm.
The regulating diaphragm is biased, on the outside of the controlled pressure chamber by a helical compression spring. The compression spring abuts a spring abutment. The compression spring and the spring abutment are contained in an inverted pot-shaped cap. A treaded spindle is mounted centrally in the cap. The spring abutment is guided on the spindle and, at the time is held against rotation in the cap. Therefore, when the spindle is rotated, the spring abutment is moved longitudinally, thereby changing the bias of the helical spring and, consequently, the set value of the controlled outlet pressure.
A sieve extends between the insert housing and the partition around the valve seat. Thereby, any dirt contained in the inflowing water is removed and kept away from the regulating value.
A tie rod extends through a longitudinal bore of the threaded spindle and is connected to the valve stem in a way, that the movement of the diaphragm is substantially not impeded. The tie rod carries a stop at its end which permits free movement of the tie rod and, thereby, of the diaphragm, during the normal operation of the pressure reducer.
The pressure reducer mechanism with spring abutment, spring, diaphragm, insert housing valve stem and valve seat forms a cartridge, which can be removed, as a whole, from the housing fitting for servicing, cleaning the sieve or replacement. When the pressure reducer mechanism is removed in this way, the tie rod serves to keep the whole mechanism together. In this state, the stop engages the end face of the spindle.
If the outlet pressure increases above the set pressure, the force on the regulating diaphragm will overcome the bias of the helical spring. The valve head will move towards the valve seat, whereby the downstream pressure will be reduced.
In the pressure reducer of EP 0,650,109 A1 the spindle is connected to a setting knob, which permits rotation of the spindle and, thereby, variation of the spring bias. When the spring bias and, thereby, the controlled output pressure has been properly set, the spindle is clamped to the cap by means of a nut.
This procedure of loosening the nut, rotating the knob and then re-tightening the nut is cumbersome. If the nut has not been properly tightened, the spindle may be unintentionally rotated and the spring bias misadjusted.